1. Field of the Invention
The present invention is broadly concerned with improved iodine-based aqueous anti-microbial compositions which include respective amounts of available iodine and non-ionic surfactant supplemented with amounts of low cost iodine-solubilizing halide ion selected from the group consisting of chloride and bromide ions and mixtures thereof. More particularly, the invention pertains to such compositions (which may be in the form of dilutable concentrates or final use solutions) which employ Cl.sup.- and/or Br.sup.- ion solubilizing halide ions in combination with non-ionic surfactants so as to sharply reduce or eliminate the need for relatively more expensive iodide ion while at the same time providing stable compositions.
2. Description of the Prior Art
Iodine-based anti-microbial compositions designed for hard surface sanitization or topical application to the skin have long been available. The former type of composition are typically used to sanitize metallic equipment surfaces, e.g., in milk-handling equipment or the like. Topically applied compositions are primarily used in product such as pre-operative antiseptic preparations, hand cleaners and in bovine teat dips for mastitis prevention. See, for example, U.S. Pat. Nos. 3,728,449 and 5,368,868 which describe detergent-iodine products.
U.S. Pat. No. 2,931,777 describes the use of non-ionic surfactants as an aid in improving the solubility of iodine in germicidal preparations. The mixtures described are generally non-aqueous solutions of iodine in a nonionic surfactant which, after preparation, can be added to water to form a use solution. As the iodine is dissolved in the non-ionic surfactant, about 14-55% of the iodine is converted to iodide ions and/or organically bound iodine. Inasmuch as only the molecular form of iodine has germicidal properties, that portion of the originally added iodine converted to iodides or organic complexes adds to the cost of the formulations without giving any germicidal effect. However, the presence of substantial iodide is necessary to keep the active molecular iodine dissolved in the aqueous solution.
U.S. Pat. No. 3,028,299 discloses the concept of adding about 0.25 parts of iodide for each part of iodine to aid in the solubilization of the iodine in solutions containing non-ionic or cationic surfactants. Addition of iodide salts directly to the non-ionic surfactant allows a slight reduction in the amount of iodide otherwise necessary to maintain the molecular iodine dissolved in solution.
U.S. Pat. No. 5,002,763 deals with complexed iodine products, and specifically water soluble complexes of polyvinylpyrrolidone (PVP), hydrogen chloride and iodine. According to the '763 patent, powdered water soluble (PVP).sub.2 HCI:I.sub.2 complexes result from a two-step preparative process involving first forming an intermediate complex with PVP powder and gaseous HCl followed by the addition of iodine.